EFFECTS OF SUBLINGUAL NIFEDIPINE ON PULSE -WAVE VELOCITY EVALUATED BYDOPPLER-ECHOCARDIOGRAPHY OF THE THORACIC AORTA

Sublingual nifedipine has a rapid and powerful hypotensive effect. Its action on arterial distensibility can be assessed by measurement of p ulse wave velocity (PWV) by Doppler echocardiography (DE). Ten patient s were used to evaluate intra-observer reproductibility (Group 1). Fif teen hypertension patients (Group 2), not taking a calcium antagonist, 64 +/- 13 years-old, were studied by DE before and 15 minutes after 1 0 mg of SL nifedipine. The following were measured : systolic and dias tolic blood pressures (SBP and DBP), heart rate (HR), echocardiographi c shortening fraction (SF) and PWV, with sternal length (SL) taken as being identical to the length of the abdominal aorta between the isthm us and the coeliac region, and by measuring DELTAt : time interval for propagation of the pulsed Doppler velocimetric wave between the isthm ic aorta and the coeliac aorta located by echocardiography : PWV = SL/ DELTAt. Evidence was found in the nifedipine group (n = 15) of a fall in SBP (159.5 +/- 27.8 cf. 140.9 +/- 21 mmHg; p = 0.002); in DBP (88.6 +/- 13 cf. 79.6 +/- 8.3 mmHg ; p = 0.005) and an increase in HR (72.3 +/- 10.7 cf. 76.8 +/- 12.9 bpm ; p = 0.04). PWV decreased after nifed ipine (10.5 +/- 3.9 cf. 7.15 +/- 12.9 bpm ; p = 0.002). There was a li near correlation between the percentage reduction in PWV and left vent ricular HR : y = 194 x - 53; r = 0.56 ; p = 0.029. Taking the study po pulation (n = 25) as a whole, there was a linear correlation between P WV and age : y = 0.14 x + 1.19 ; r = 0.55 ; p = 0.04. Taking all measu rements (n = 50), there was a correlation between SBP and PWV (y = 0.0 4 x + 1.71 ; r = 0.35 ; p = 0.02). SL nifedipine lowered blood pressur e, which was accompanied by a fall in PWV, reflecting arterial distens ibility. Doppler echocardiography would appear to be a technique appro priate for routine use in the evaluation of PWV and its variations.